Mount Prospect, Illinois 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

658
FXUS63 KLOT 011734
AFDLOT

Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
1134 AM CST Sun Feb 1 2026

.KEY MESSAGES...

- A period of light snow accumulations are likely (60%+ chance)
  tonight into early Monday morning, followed by less cold
  conditions by midweek.

&&

.DISCUSSION...
Issued at 245 AM CST Sun Feb 1 2026

A much quieter start to the day compared to the last two with a
surface ridge shifting across Illinois. A mid-lake convergent
axis from Saturday has persisted this morning owing to a modest
land breeze off Lower Michigan and northern Indiana. An
associated narrow corridor of stratus extending southward along
the Illinois shore and across northwest Indiana may be able to
squeeze out a few flurries, but observed cloud depths appear too
shallow to support anything more.

A pair of well-defined mid-level waves over the eastern Dakotas
this morning will track southeastward through tonight, with the
southern wave becoming increasingly sheared over southern
Illinois this afternoon and the northern wave weakening over
Wisconsin this evening. Another wave currently over Saskatchewan
will phase into the northern wave overnight. Meanwhile, a 110
knot upper-level jet will pass southwest of the area. Given
sufficient mid-level moisture observed upstream but weak ascent
from the lack of formidable forcing, expectations are for an
axis of very light snow to drift across the CWA from west to
east early this evening through sunrise Monday. Accumulations up
to one half inch are possible areawide, though would not be
surprised to see an area with little to no accumulation where
(most likely the southwest CWA) the weak forcing is split by the
jet to the south and wave to the north.

Mid-level moisture will quickly exit Monday morning, but
lingering low-level moisture and diurnal processes may result in
some flurries across the area midday.

A conglomeration of several waves loosely phasing across the
central and southern Great Plains on Tuesday will induce an
elongated surface trough across the lower half of the
Mississippi River Valley. As the northernmost wave digs
southeastward from the Dakotas to southern Illinois Monday night
into Tuesday, a narrow frontogenesis/deformation axis pivoting
on the north side of the wave has a <20% chance for accumulating
snow to brush the far southern CWA. Have maintained a dry
forecast as trends in ensemble guidance have been toward a drier
and more southern solution with time.

A rather marginal lake-effect snow set-up into northwest
Indiana and along the Illinois shore will then be the next focus
for precip Tuesday night into Wednesday morning. Low inversion
heights and borderline thermo profiles indicate the precip will
be limited to isolated to scattered light showers. Have included
chance PoPs with little accumulation during this window.

Broader northwest flow will persist midweek through next
weekend. Temps may moderate to above freezing by Thursday or
Friday, which would be the first time in around three weeks for
much of the area. This would also come with a potential for
more active weather in the region late in the week, with chances
of accumulating snow and perhaps mixed precip. A return to
colder conditions should then prevail next weekend.

Kluber

&&

.AVIATION /18Z TAFS THROUGH 00Z TUESDAY/...
Issued at 1134 AM CST Sun Feb 1 2026

Forecast concerns include...

Period of light snow expected tonight.
Mvfr cigs tonight into Monday morning.

Light snow currently over eastern IA and far western IL is
expected to dissipate as it slowly moves southeast and remain
southwest of the terminals. Some flurries are possible at RFD by
late this afternoon. An additional area of snow across eastern
MN will move southeast into the area this evening bringing a
period of light snow to all the terminals. This snow is expected
to be rather light and there remains uncertainty for how low the
visibility may drop. Maintained tempo 2sm at RFD and 3sm at the
rest of the tafs for now, but as trends emerge later this
evening, these may need to be adjusted and its possible a 2-3
hour period of prevailing light snow may be needed. This snow is
expected to move east of the terminals before daybreak Monday
morning though flurries will be possible through midday.

Mvfr cigs are expected once the snow begins later this evening.
Brief ifr cigs are also possible, depending on how widespread
the snow becomes. Low mvfr cigs are likely to continue through
mid morning Monday, scattering out from west to east, though
only medium confidence for cig trends Monday.

South/southwest winds may periodically gust into the 15-20kt
range this afternoon and then diminish this evening, turn
southwesterly overnight and west/northwest Monday morning. cms

&&

.HYDROLOGY...
Issued at 245 AM CST Sun Feb 1 2026

River gauges, reports from local officials, and reports from
trained ice spotters continue to indicate a few ice jams across
the area. Additional ice formation should slow with daytime
temperatures mainly in the 20s to low 30s through the upcoming
week. While no widespread flooding is expected, localized ice
jams may still develop.

- NWS Chicago

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...None.
IN...None.
LM...None.

&&

$$

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